Time-of-flight generating circuit and chip, flow meter and method of the same

Abstract

The application discloses a time-of-flight generating circuit, coupled to a first transducer and a second transducer, wherein there is a distance greater than zero between the first transducer and the second transducer, and a fluid having a flow speed flows sequentially through the first transducer and the second transducer, wherein the time-of-flight generating circuit includes: a transmitter, coupled to the first transducer; a receiver, coupled to the second transducer; a signal processing circuit, coupled to the transmitter and the receiver; and a correlation circuit, a measuring circuit and a transformation circuit, coupled to the signal processing circuit. The application also discloses a chip, flow meter, and method of the same.

What is claimed is: 
     
       1. A time-of-flight (TOF) generating circuit, coupled to a first transducer and a second transducer, wherein there is a distance greater than zero between the first transducer and the second transducer, and the first transducer and the second transducer are arranged in a pipeline filled with fluid, wherein the TOF generating circuit comprises:
 a transmitter, coupled to the first transducer; 
 a receiver, coupled to the second transducer; 
 a signal generating circuit, configured to, under a first ambient factor, generate a first signal to the transmitter to cause the first transducer transmit a first transducer signal, wherein the first transducer signal is received by the second transducer and the receiver generates a reference signal to the signal generating circuit; and, under a second ambient factor, generate a second signal to the transmitter to cause the first transducer transmit a second transducer signal, wherein the second transducer signal is received by the second transducer and the receiver generates an input signal to the signal generating circuit; 
 a correlation circuit, configured to at least receive the input signal to perform a correlation operation to generate a correlation signal; and 
 a measuring circuit, configured to generate a measurement signal according to the correlation signal, wherein the measurement signal indicates a phase difference between the input signal and the reference signal, and the measurement signal includes a first measurement signal and a second measurement signal, wherein the first measurement signal is configured to indicate a phase compensation of the input signal and the reference signal, and the second measurement signal is configured to indicate a phase offset of the first transducer and the second transducer; and 
 a transformation circuit, configured to selectively transform the measurement signal or the first measurement signal from a frequency domain to a time domain to generate a TOF difference signal, wherein the T F difference signal is configured to indicate a difference of flight times between the first transducer and the second transducer. 
 
     
     
       2. The TOF generating circuit of  claim 1 , further comprising:
 a processing circuit, configured to control the TOF generating circuit to selectively operate in a first mode or a second mode to perform different calibrations on the TOF generating circuit. 
 
     
     
       3. The TOF generating circuit of  claim 2 , wherein, in the first mode, the correlation circuit receives the input signal and generates the correlation signal according to the input signal and the reference signal, and the transformation circuit transforms the first measurement signal from the frequency domain to the time domain, to generate the TOF difference signal. 
     
     
       4. The TOF generating circuit of  claim 2 , further comprising:
 a compensation circuit, coupled to the measuring circuit and configured to perform a compensation operation on the input signal to generate a compensation signal according to the first measurement signal in the second mode. 
 
     
     
       5. The TOF generating circuit of  claim 4 , further comprising:
 a synthesis circuit, coupled to the compensation circuit and the signal generating circuit and configured to synthesize the reference signal and the compensation signal by using a specific ratio to generate a synthesized signal and output the synthesized signal to the correlation circuit. 
 
     
     
       6. The TOF generating circuit of  claim 5 , wherein the synthesized signal is expressed by the following equation:
 the synthesized signal (n−1)/n*the reference signal+1/n*the compensation signal, wherein n is an integer greater than 1. 
 
     
     
       7. The TOF generating circuit of  claim 5 , wherein, in the second mode, the correlation circuit receives the input signal and the synthesized signal to generate the correlation signal, and the transformation circuit transforms the measurement signal from the frequency domain to the time domain to generate the TOF difference signal. 
     
     
       8. The TOF generating circuit of  claim 1 , further comprising:
 a compensation circuit, coupled to the measuring circuit and configured to perform a compensation operation on the input signal according to the phase compensation, and generate a compensation signal after performing the compensation operation. 
 
     
     
       9. The TOF generating circuit of  claim 8 ; further comprising:
 a synthesis circuit, coupled to the compensation circuit and configured to synthesize the reference signal and the compensation signal by using a specific ratio to generate a synthesized signal and output the synthesized signal to the correlation circuit, so that the correlation circuit receives the input signal and the synthesized signal to generate the correlation signal. 
 
     
     
       10. The TOF generating circuit of  claim 1 , wherein, the first ambient factor and the second ambient factor comprise a difference in ambient temperature and/or the flow speed. 
     
     
       11. A flow meter, comprising:
 the TOF generating circuit of  claim 1 . 
 
     
     
       12. A chip, comprising:
 a TOF generating circuit, coupled to a first transducer and a second transducer, wherein there is a distance greater than zero between the first transducer and the second transducer, and the first transducer and the second transducer are arranged in a pipeline filled with fluid: 
 wherein the TOF generating circuit comprises:
 a transmitter, coupled to the first transducer; 
 a receiver, coupled to the second transducer; 
 a signal generating circuit, configured to, under a first ambient factor, 
 
 generate a first signal to the transmitter to cause the first transducer transmit a first transducer signal, wherein the first transducer signal is received by the second transducer and the receiver generates a reference signal to the signal generating circuit; and, under a second ambient factor, generate a second signal to the transmitter to cause the first transducer transmit a second transducer signal, wherein the second transducer signal is received by the second transducer and the receiver generates an input signal to the signal generating circuit; 
 a correlation circuit; configured to at least receive the input signal to perform a correlation operation to generate a correlation signal; and 
 a measuring circuit, configured to generate a measurement signal according to the correlation signal, wherein the measurement signal indicates a phase difference between the input signal and the reference signal, and the measurement signal includes a first measurement signal and a second measurement signal; wherein the first measurement signal is configured to indicate a phase compensation of the input signal and the reference signal, and the second measurement signal is configured to indicate a phase offset of the first transducer and the second transducer; and 
 a transformation circuit, configured to selectively transform the measurement signal or the first measurement signal from a frequency domain to a time domain to generate a TOF difference signal, wherein the TOF difference signal is configured to indicate a difference of flight times between the first transducer and the second transducer. 
 
     
     
       13. A TOF generation method, configured to control a transmitter and a receiver, wherein the transmitter is coupled to a first transducer, and the receiver is coupled to a second transducer, wherein there is a distance greater than zero between the first transducer and the second transducer, and the first transducer and the second transducer are arranged in a pipeline filled with fluid, wherein the TOF generation method comprises:
 under a first ambient factor, generating a first signal to the transmitter to cause the first transducer transmit a first transducer signal; 
 after the first transducer signal is received by the second transducer, generating a reference signal by using the receiver; 
 under a second ambient factor, generating a second signal to the transmitter to cause the first transducer transmit a second transducer signal; 
 after the second transducer signal is received by the second transducer, generating an input signal by using the receiver; 
 at least receiving the input signal to perform a correlation operation to generate a correlation signal; 
 generating a measurement signal according to the correlation signal, wherein the measurement signal indicates a phase difference between the input signal and the reference signal, and the measurement signal comprises a first measurement signal and a second measurement signal, wherein the first measurement signal is configured to indicates a phase compensation of the input signal and the reference signal, and the second measurement signal indicates a phase offset of the first transducer and the second transducer; 
 selectively transforming the measurement signal or the first measurement signal from a frequency domain to a time domain to generate a TOF difference signal, wherein the TOF difference signal is configured to indicate a difference of flight times between the first transducer and the second transducer. 
 
     
     
       14. The TOF generation method of  claim 13 , further comprising:
 selectively operating in a first mode or a second mode to perform different calibrations on the TOF generating circuit. 
 
     
     
       15. The TOF generation method of  claim 14 , wherein the at least receiving the input signal to perform the correlation operation to generate the correlation signal comprises:
 in the first mode, receiving the input signal and generates the correlation signal according to the input signal and the reference signal, and 
 the selectively transforming the measurement signal or the first measurement signal from the frequency domain to the time domain to generate the TOF difference signal comprises:
 transforming the first measurement signal from the frequency domain to the time domain to generate the TOF difference signal. 
 
 
     
     
       16. The TOF generation method of  claim 14 , further comprising:
 in the second mode, performing a compensation operation on the input signal according to the phase difference to generate a compensation signal. 
 
     
     
       17. The TOF generation method of  claim 16 , further comprising:
 synthesizing the reference signal and the compensation signal by using a specific ratio to generate a synthesized signal. 
 
     
     
       18. The TOF generation method of  claim 17 , wherein the synthesized signal is expressed as:
 the synthesized signal=(n−1)/n*the reference signal±1/n*the compensation signal, wherein n is an integer greater than 1. 
 
     
     
       19. The TOF generation method of  claim 16 , wherein, the at least receiving the input signal to perform the correlation operation to generate the correlation signal comprises:
 in the second mode, receiving the input signal and the synthesized signal to generate the correlation signal; and 
 the selectively transforming the measurement signal or the first measurement signal from the frequency domain to the time domain to generate the TOF difference signal comprises:
 transforming the measurement signal from the frequency domain to the time domain to generate the TOF difference signal. 
 
 
     
     
       20. The TOF generation method of  claim 13 , wherein the first ambient factor and the second ambient factor comprise a difference in ambient temperature or flow speed of the fluid.